This name is a synonym of Nematanthus perianthomegus (Vell.) H.E. Moore.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50261140) with original publication details: Fl. Flumin. 257 1825.
This name was in version 1 of The Plant List, record tro-50261140, and has not been changed.